Certain diseases or conditions may be treated, according to modern medical techniques, by delivering a medication fluid or other substance to the body of a patient, either in a continuous manner or at particular times or time intervals within an overall time period. For example, diabetes is commonly treated by delivering defined amounts of insulin to the patient at appropriate times. Some common modes of providing insulin therapy to a patient include delivery of insulin through manually operated syringes and insulin pens. Other modern systems employ programmable fluid infusion devices (e.g., insulin pumps) to deliver controlled amounts of insulin to a patient.
A fluid infusion device suitable for use as an insulin pump may be realized as an external device or an implantable device, which is surgically implanted into the body of the patient. External fluid infusion devices include devices designed for use in a generally stationary location (for example, in a hospital or clinic bedside environment), and devices configured for ambulatory or portable use (to be carried or worn by a patient). External fluid infusion devices may establish a fluid flow path from a fluid reservoir or cartridge to the patient via, for example, a suitable hollow tubing, needle, or other type of fluid conduit.
A fluid infusion device can be implemented with a rotary micropump mechanism that accurately delivers a precise volume of fluid with each revolution or cycle. The inlet of the micropump is connected to a fluid source such as a reservoir, and the outlet of the micropump is connected to a fluid delivery conduit that leads to the body of the patient. Under normal operating conditions, the micropump draws fluid from the fluid source (via a vacuum or suction action) and then delivers a predictable volume of fluid with each cycle.
It is desirable to reliably and accurately detect at least two conditions, for purposes of alerting the user and/or to otherwise control the operation of the fluid infusion device in a responsive manner. One of these “fault” conditions is a downstream occlusion in the fluid delivery path (e.g., a blockage downstream from the outlet of the micropump). Another “fault” condition is an upstream occlusion (e.g., a blockage located before the inlet of the micropump). In this regard, an empty fluid reservoir can be considered to be an upstream occlusion because continued operation of the micropump in the presence of an empty reservoir does not result in the normally expected delivery of fluid.
Accordingly, it is desirable to have a fluid infusion device and related operating methodologies that effectively detect upstream and/or downstream occlusions in the fluid delivery pathway associated with a rotary micropump. In addition, it is desirable to provide an improved rotary micropump having certain features and functionality that facilitate the detection of upstream and/or downstream occlusions in the fluid delivery pathway. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.